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Another audi question.....

Discussion in 'In-Car Entertainment' started by audi-a6, Jul 18, 2013.

  1. audi-a6
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    audi-a6 Member

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    so, ill tell you the set up then the problem. So, i got an orion hcca 15.2 in a ported enclosure 40 inch wide
    17 inch height 14 inch depth. and a Hifonics 2000w rms amp. The problemis that i cant seem to hit certain notes in music, for example, everyone knows the david gehetta song, "titanium" at the start of the song (first 16 seconds) is just intro, no bass, then up to 31 seconds, you got a kind high bass, then kicks in to hard bass. But, on my system you dont get any bass untill the 31 seconds, it wont play the higher bass note, it does it on alot of songs, its really annoying coz at certain points of songs/music it just sounds like i have no sub, iv tried adjusting seetings on amp and stereo, but no joy..... could it be the enclosure? too big?
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  2. dualmono21
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    dualmono21 Active Member

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    ported enclosure that wont play music ...
    i seem to remember someone mentioning this not so long ago

    how big is the enclosure supposed to be internally ? from the measurements youve given me that equates to 5.5 cuft
    which is about 2 cu ft too big
    how big is the port ??
    whats the tuning frequency ???
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  3. audi-a6
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    audi-a6 Member

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    yeah that what i thought, but remember the sub is massive 30kg magnet! Subs displacement is 0.37704 dont know the tuning frequency but port is about 2" x 15" so about right, was thinking maybe to just put a panel inside box to reduce the volume of enclosure
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  4. DarkBunny
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    DarkBunny Member

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    Sounds like you've got the filter tuned on either the amp or head unit (or both) to cut off to high.

    Have you set any LPFs (low pass filter settings) on your head unit?
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  5. dualmono21
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    dualmono21 Active Member

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    you dont know the tuning frequency yet you know the port size and say its about right ...

    your a country mile away im afraid
    to do this properly you need a program like winisd which will work out the box area and ideal port size and length for you

    ive entered the box size of about 5.0 cu ft after woofer displacement and used a tuning frequency of 30hz
    and with a 2" port it give a port length of 1/2"

    you need to rethink this quickly before you blow the amplifier up
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  6. audi-a6
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    audi-a6 Member

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    port length 1/2"? i only say its about right as that's the recommended port size on the speaker specs, however the enlosure volume is more than the specs recommend, their is a sub frequency control on the head unit, but it is set to the lowest setting 30hz other than that all the settings are off, ie hpf there is no lpf on the head unit as such, on the amp the control runs from 35hz to 250hz iv got it set at around 10 o'clock if you know what i mean and to be honest that sounds crap at high volume, my last subs (run of the same head unit) played perfect and hit every low and every high, so i dont think its the head unit
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  7. cocain
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    cocain RAA RAA like a dungeon dragon!

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    I would listen to dual mono he really does know what he is going on about :)
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  8. audi-a6
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    audi-a6 Member

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    no doubt he knows what he is on a bit, he's been a great help from the start, but im confused as what im suposed to be listening to?

    I have spoke to the company that made my enclosure..... the enclosure is tuned to 33hz the volume of the box is 3.5 cubic feet, i said to them that my calculations add to over 5 cu ft but they said that you have to take the port displacement into consideration which does equal to 3.5 cu ft........ so the problem must lie with the amp or head unit going to see if i can just keep adjusting the settings or take it to my local audio center and ask them to do it.
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  9. dualmono21
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    dualmono21 Active Member

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    what is sub frequency control ???? is this the crossover point or is it an equalisation point
    you need to read the manual of the headunit

    crossover point needs to be around 50hz with that size sub

    if the headunit has low pass filters and high pass are these adjustable on the front channels only or are they adjustable on the
    sub channel

    r.t.f.m
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  10. dualmono21
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    dualmono21 Active Member

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    port displacement of 1.5cu ft ....

    port displacement is the equivalent airspace used by the external measurments of the port itself
    in your case 2" diameter x 15" long that isnt 1.5cuft
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  11. audi-a6
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    audi-a6 Member

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    those measurements are the port width and hieght, the port length is a lot longer as it goes round the box....

    as for the sub frequency controll this is what the manual says

    "Each time MULTI-CONTROL is pushed left orright, cut-off frequencies are selected in the
    following order:
    50Hz—63Hz—80Hz—100Hz—125Hz
    Only frequencies lower than those in the selected
    range are outputted from the subwoofer"

    So i have it set on the lowest 50hz (not 30hz) is that right? I have tried it on a higher setting but does not make any difference. also i have a similar control on the amp "sub sonic filter" that is also set on the lowest, which is 35 but i believe its the opposite isnt it, "will not play lower than the selected frequency" Could they be interfering with each other? as there is no way to turn them off completely. Just thinking about it now, between my amp and head unit my sub is prevented from playing lower than 35hz and higher than 50hz??? thats got to be my problem?
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  12. dualmono21
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    dualmono21 Active Member

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    port height is only applicable to slotted ports not to round ones
    so which one do you have ??? i have been working all the calculations out on a 2" diameter round port 15" long

    yes

    you have the crossover set correctly on the headunit ... but id still like to know what crossover slope it is
    and the subsonic filter at 35hz is a complete waste of time it ideally wants to be 20hz
    you could try turning it off , but be very carefull with the volume control as the woofer may unload on certain notes
    and destroy the woofer and the amplifier

    the other thing to try is blocking the port up completely with rags or towels ... does it sound better ???

    now you know why i suggested a simple sealed enclosure
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  13. audi-a6
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    audi-a6 Member

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    Yeah its a slot port, I did try blocking it off but tbh it sounded worse, no way near as much volume.... my mistake again ref the sub sonic it goes from 15hz to 35hz, iv set that at around half way also set stereo to 80hz and it does sound much better, but still not perfect.... ill just have to stick to listening to drum and bass lol as that sounds the best :) but would reducing the inside volume of the box make in difference ie louder or quieter i guess it wont hit really low notes as it does now?

    Also on another subject ref: amped 6x9's I had a pair of infinity 693.11i's running off a vibe vp2 amp (2 x 150w rms @ 2 ohm) i managed to blow one of them, to be more specific one of the resistors to the mid range/tweeter exploded, any way, the company replaced them for me and obviously i dont want to do it again. So, setting them up properly I started to follow the instructions from crutchfield, it states turn volume to max and slowly turn the gain up untill they distort..... but they dont distort and i dont want to keep the gain all the way up, I have the amp set on hp crossover with the hpf adjusted down to around 190hz so they dont sound too tinnie if you know what i mean. What else can i do i dont want to turn my stereo right up and blow them but i belive i can get a few more db's out of them. what would you suggest?
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  14. audi-a6
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    audi-a6 Member

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    also, could a better head unit make any difference to the sub, I got a pioneer deh-p85bt at mo
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  15. audi-a6
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    audi-a6 Member

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    Isnt the point of a "gain" control to match input sensitivity to the head unit, the vp2 amps can run from 250mv to 4v and my stereo is 4v? so does that mean i can have it all the way up? I dont think so......
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  16. dualmono21
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    dualmono21 Active Member

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    you cannot have everything so pick which you want

    do you want it loud or do you actually want to play music ??? if you simply want it loud enough that the people in the next street can hear you coming , leave it like it is , but it will sound crap to both you and everyone else

    if you actually want to listen to music put the woofer in a 2cuft sealed enclosure and turn off the subsonic filter

    to set the speakers up properly you need an oscilloscope , you cant just keep winging it and hoping for the best

    the gain on an amplifier is to level match to the source not to increase volume
    it should be set so as to give you full control of the volume , not so it becomes very loud very quickly

    if your headunit is 4 volts out then it shouldnt need the amplifier turning up at all there should be enough signal coming from the headunit

    if your headunit only output 250mv then you would need to gain the amplifier up as its not getting enough signal to produce maximum power
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  17. audi-a6
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    audi-a6 Member

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    oh right...... so just leave the gain al the way down then? I wont get any clipping or any thing like that?
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  18. audi-a6
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    audi-a6 Member

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    and going back to the gain, if my hifonics amp for sub has a gain from 9v to 0.2v, i should set that at just past half...


    at least i know now why my 6x9's blew.... i had the gain set at around 3/4 lol
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  19. dualmono21
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    dualmono21 Active Member

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    NO!!!

    you need to have the kit set up properly
    you need the kit setting up with the use of an oscilloscope , then and only then will it be o.k to turn it up without risk of it blowing something up

    you need to scope the headunit to find out at what point does it clip ...can it be turned up full without it clipping or if not at what point does it clip

    you then need to do the same with the amplifier and find out where the amplifier starts clipping ...maximum unclipped input from the headunit and watch the amplifier for putting out a clipped output .... this is where you can afford to turn it up to without risk of it breaking something
    then the same with the vibe vp2 maximum unclipped input until it just starts to clip , this is where its safe to have the amp turned up .... you then need to ensure the low frequency stuff isnt going through the 6 x 9 speakers so high pass these at around 80hz
    or better still put them in small sealed boxes
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  20. audi-a6
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    audi-a6 Member

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    yeah they are set on hpf.... I aint got access to oscilloscope and dont really want to buy one lol..... what does clipping sound like, is it same as distortion? can i even hear it? to stay safe iv turned my amps right down to the lowest level, although if i turn head unit right up its not really that loud... iv got a db reader on my phone, i know its not going to be acurate but still, it dont go higer than about 93 db, i believe just the 6x9's alone should go over 100db surely...
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  21. audi-a6
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    audi-a6 Member

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    I dont suppose your going to AITP next month are you?
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  22. dualmono21
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    dualmono21 Active Member

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    db readings are nothing whatsoever to do with set up

    you do not seem to grasp that the equipment you have is extremely sensitive and needs proper set up ... if you do not set it up properly it will shorten its life span severely and very possibly blow the entire system up
    i find it frustrating that you have spent so much money on the kit and wont spend £50 on getting it set up properly

    clipping is the point where a signal loses integrity and no longer has enough clean power to generate a sign wave of the correct magnitude
    if this comes from the headunit .... you are amplifiying this through to the speakers .... this in turn makes the speakers distort and overheat , when this happens the voice coil gets too hot and the glue melts in the speaker and seizes inside the speaker .... when this happens and the amplifier is still trying to drive the speaker that is seized it can cause the impedance to go way below what is reccomended .... this in turn blows the amplifier up .... this in turn can send a voltage signal back down the rca,s and blow up the headunit

    all this for £50 or taking it back to where you bought it and have it professionally set up

    i will make it down to aitp sometime but probably not the next one my car isnt quite ready
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  23. dualmono21
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    dualmono21 Active Member

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  24. audi-a6
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    audi-a6 Member

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    are they easy enough to use? or would it be better to just go down my local audio shop and pay them to set it up?
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  25. dualmono21
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    dualmono21 Active Member

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    yes

    you dont really need much else apart from a few test tones
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  26. audi-a6
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    audi-a6 Member

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    Cool, will give it ago then, thanks for your help mate, really appreciate it... Well let you know how I get on :)
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  27. dualmono21
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    dualmono21 Active Member

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    let me know when you get the oscilloscope and i will guide you through exactly how to use it and more importantly
    WHY you are using it
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  28. audi-a6
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    audi-a6 Member

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    will do, spoke to my local audio shop and they going to lend me one lol save's the pennys, will pick it up during the week. Thanks Buddy
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